The present invention relates to a power stabilizing unit and more particularly relates to a power stabilizing unit for use in an internal combustion engine.
In conventional batteryless internal combustion engines, a crankshaft is forcibly rotated using a kick lever or a starting rope to rotate a generator (ACG) coupled to the crankshaft so that generated drive power is used to drive control circuits etc. for an internal combustion engine mounted on a vehicle, such as a motorcycle, snowmobile, etc.
In such conventional batteryless internal combustion engines, insufficient power may be generated by the kicking action, an output of the main power supply circuit (regulator rectifier) may be intermittent, and spike-shaped drops may occur in the power supply voltage due to the output power of the ACG being temporarily insufficient due to large rush currents when a lamp load is switched on or various other loads, such as pulse-shaped currents of an injector, igniter, etc. A particularly dramatic drop occurs in the power supply voltage when an inrush current, occurring when the turn indicator lamps are switched on, overlaps with injector or ignition coil driving.
This drop is particularly large and may cause the engine to stop when the drop in the power supply voltage falls below a minimum operating voltage of the engine control unit. Even if the engine does not stop, dramatic fluctuations in the power supply voltage may be detrimental to the discharge precision of the injector and may cause the ignition voltage to be insufficient.
One solution for compensating for power supply voltage fluctuations is to provide a power stabilizing circuit including a diode and a capacitor between the generator and the control circuit. Such a power stabilizing circuit is described, for example, in Japanese Examined Utility Model Application Publication No. Hei. 8-9393). However, in the above publication, the power supply voltage of the control circuit is stabilized by connecting an injector load to the output of the main power supply circuit, connecting the control circuit power supply via a diode, and providing a capacitor at this location. However, deterioration of injector discharge reliability is unavoidable because the injector power supply voltage is not stable.
Another proposed solution is to make the capacitance of the capacitor large. Unfortunately, it takes time for the power supply voltage of the power supply circuit to rise in order to charge the capacitor when kick-starting with this kind of batteryless system.
Specifically, engine rotation due to kick-starting takes place for approximately 0.2 to 0.4 seconds. During this time, the time required for activation of the injection system becomes substantially shortened due to charging of the capacitor and in the worst case, the supply of power is stopped prior to the injection system reaching the start-up power supply voltage.
The present invention provides a power stabilizing unit for an internal combustion engine capable of stably providing drive power to a control circuit of the internal combustion engine and capable of rapidly starting up the control circuit.
In at least one embodiment, the present invention is directed to a power stabilizing unit for supplying drive power to at least one control circuit for controlling an internal combustion engine and at least one other load, comprising a main power supply circuit for regulating drive power, a capacitor, connected to the main power supply circuit, for storing electrical power supplied by the main power supply circuit, a current control circuit for supplying electrical power, supplied by the main power supply circuit, to the at least one control circuit and/or said at least one other load but not to the capacitor when a voltage outputted by the main power supply circuit is less than a first set voltage, and supplying electrical power from the main power supply circuit to the capacitor when the voltage outputted by the main power supply circuit is greater than or equal to the first voltage, and a discharge circuit for supplying electrical power accumulated in the capacitor to said at least one control circuit and/or the at least one other load when the output voltage of the main power supply circuit falls to a voltage equal to or less than the capacitor voltage.
In at least one embodiment, the present invention is directed to a power stabilizing unit further comprising a short circuiting circuit including a switching element provided across said capacitor and said main power supply circuit such that said capacitor and said main power supply circuit are short-circuited by putting the switching element on when a voltage outputted from said main power supply circuit becomes greater than or equal to a second voltage.
In at least one embodiment, the present invention is directed to a power stabilizing unit, wherein the path of the short circuit is controlled by a microcomputer.
In at least one embodiment, the present invention is directed to a power stabilizing unit, wherein the switching element is a relay.
In at least one embodiment, the present invention is directed to a power stabilizing unit, wherein the switching element is an FET.
In at least one embodiment, the present invention is directed to a power stabilizing unit, wherein the switching element is capable of holding an on state using a self-holding function.
In at least one embodiment, the present invention is directed to a power stabilizing unit, wherein the switching element is capable of releasing the self-holding function by turning a main switch, used in starting and stopping the internal combustion engine, off.
In at least one embodiment, the present invention is directed to a power stabilizing unit for an internal combustion engine, further comprising a diode provided between said main power supply circuit and said voltage detection circuit, so that the at least one other load is connected between the diode and said main power supply circuit.
In at least one embodiment, the present invention is directed to a power stabilizing unit, further comprising a main switch, either connected at an input side of said at least one control circuit, or at an output side of said main power supply circuit.
In at least one embodiment, the present invention is directed to a power stabilizing unit, wherein said power stabilizing unit is part of a power supply unit, wherein said main power supply circuit is connected to a generator for generating electrical power.
In at least one embodiment, the present invention is directed to a power stabilizing unit, wherein said power stabilizing unit is part of a power supply unit, said power supply unit further including a generator for generating electrical power.
In at least one embodiment, the present invention is directed to a power stabilizing unit, wherein said power stabilizing unit is part of a power supply unit, which is further part of an internal combustion engine.
In at least one embodiment, the present invention is directed to a power supply unit for supplying drive power to at least one control circuit for controlling an internal combustion engine and at least one other load, comprising a generator for generating electrical power, a main power supply circuit for regulating drive power, a capacitor, connected to the main power supply circuit, for storing electrical power supplied by the main power supply circuit, a current control circuit for supplying electrical power, supplied by the main power supply circuit, to the at least one control circuit and/or said at least one other load but not to the capacitor when a voltage outputted by the main power supply circuit is less than a first set voltage, and supplying electrical power from the main power supply circuit to the capacitor when the voltage outputted by the main power supply circuit is greater than or equal to the first voltage, and a discharge circuit for supplying electrical power accumulated in the capacitor to said at least one control circuit and/or the at least one other load when the output voltage of the main power supply circuit falls to a voltage equal to or less than the capacitor voltage.
In at least one embodiment, the present invention is directed to an internal combustuion engine, comprising a generator for generating electrical power, a main power supply circuit for regulating drive power, a capacitor, connected to the main power supply circuit, for storing electrical power supplied by the main power supply circuit, a current control circuit for supplying electrical power, supplied by the main power supply circuit, to at least one control circuit and/or at least one other load but not to the capacitor when a voltage outputted by the main power supply circuit is less than a first set voltage, and supplying electrical power from the main power supply circuit to the capacitor when the voltage outputted by the main power supply circuit is greater than or equal to the first voltage, and a discharge circuit for supplying electrical power accumulated in the capacitor to said at least one control circuit and/or the at least one other load when the output voltage of the main power supply circuit falls to a voltage equal to or less than the capacitor voltage.